Dual acting brake actuator

Abstract

A braking mechanism linkage for use in a braking system can be applied by ther a service brake actuator or a parking brake actuator to brake a tracked vehicle. Each actuator when applied to the linkage results in a different type of linkage motion to apply a single brake. The parking brake mode has a locking mechanism associated therewith to keep the brake applied until released to prevent motion of the vehicle until the parking brake is released. The service braking mode returns to an unengaged position upon release of the actuator.

What is claimed is: 
     
       1. A brake linkage designed to be connected to both a parking brake actuator and a service brake actuator for a tracked vehicle, the linkage also being connected to a brake associated with the power output of a transmission which drives the tracked vehicle, the linkage serving to transfer braking forces from the actuators to the brake to effect a braking action on the power output, the force applied being dependent on the actuator used to apply the braking force to the linkage, the linkage comprising: a base rigidly mounted to the vehicle, a pair of bosses mounted on the base and extending from the surface of the base, a pair of parallel slide bars, one rail extending through each of the bosses, the bars mounted so they can slide relative to the bosses, a slide assembly having first and second plates mounted rigidly together in a parallel configuration by a center web, the slide bars passing through apertures in the first and second plates so the plates can move relative to the slide bars, the one end of the slide bars having a stop in contact with the outer surface of the second plate so movement of the slide bar in one direction will pull the slide assembly in the direction of the slide bars movement, the other end of the slide bars being attached to a trace, the trace being mounted transversely to the motion of the slide bars, biasing means associated with the trace tending to pull the trace to an unengaged position, a hydraulically actuated ram mounted on the base, the ram being attached to center of the trace, the ram being responsive to actuating forces of the parking brake actuator by a driver to pull the slide rails and thereby the slide assembly, the ram having an extension extending beyond the trace, a locking means mounted so as to receive and hold the extension keeping the ram extended against the biasing means until the locking means is released, a service brake cable having one end connected to the service brake actuator and the other end passing through an aperture in the first plate, the end of the service brake cable having a flange located on the inside of the slide assembly so that when the service brake actuator is activated but the cable moves the flange and pulls the slide assembly to activate the brake the movement of the slide assembly by one of the actuators will not move the parts of the other actuator, and an attachment means attached to the slide assembly and the brake so that when the slide assembly is moved by either actuator, the brake will be applied.